Plant polysaccharide supplements reduce the expression of pro-inflammatory genes in colonic tissue of mice with dextran sulfate sodium-induced colitis

Oral ingestion of polysaccharides can elicit immunomodulatory effects, both systemically and in the gut, but their mechanisms of action are not well understood In a recent study, two aloe vera gel-based mixed polysaccharide dietary supplements (Advanced Ambrotose^® powder and Ambrotose^® complex) protected rats against dextran sulfate sodium (DSS)-induced ulcerative colitis (UC). To better understand the mechanisms by which these supplements protect against colonic inflammation, we examined the effect of supplement feeding, with exposure to 5% DSS during the last eight days, on colonic gene activity in mice. DSS exposure without supplement feeding induced symptoms of colitis and potently increased expression of genes associated with inflammation, immune cell activation, and pathogen recognition and signaling. Feeding of supplements reduced DSS-induced disease activity, partially prevented colonic shortening, and reduced the expression of colonic proinflammatory, immune cell activation, and pathogen-recognition and signaling genes. Interestingly, ingestion of Advanced Ambrotose^® powder down-regulated the expression of several genes associated with inflammation, and decreased the expression of genes associated with cell activation in healthy animals. This study demonstrates that DSS-induced colitis results in induction of several genes responsible for inflammation and that ingestion of these polysaccharide supplements can ameliorate some of the symptoms of colitis, possibly through suppression of these genes.